In terms of composition, great!
Mix and instrumentation wise, there are some things I would change. For one, the mix is pretty quiet and it sounds to be unmastered. Some compression would do you lots of favors applied to the master channel -- careful to do this once you are satisfied with how you want your song to be, and not during the entire process. Even an internet mastering service would help.
In terms of individual instruments, your lead guitar is a little dry sounding. It could use a chorus, delay, or reverb to give it some space. The same is occurring with most other leads, so they sound flat.
Your rhythm guitars could be double tracked
Your kick and snare should be the loudest parts of your mix. hi-hats are a bit too loud. They should be audible but not overly obvious.
Brass could also be panned wider for effect and other instruments used to double this part for extra texture
The breathing SFX through 1:26 could be panned left or right for effect
Otherwise, hold onto this idea. It's a fantastically written piece that just needs some polish!